lincoln memorial, gleaming in the distance. there they are. some 800,000 people expected to see the president publicly sworn in, for the second time, today. and to that end, a lot of hollywood star power making the trip to the nation's capital, as well. a-list celebrities, many of them long-time supporters of the president, flocking here to the nation's capital, to help him kick off his second term in style. take a look. ♪ baby, you're a firework >> reporter: inauguration weekend began with some fireworks. music's hottest names, from katy perry. >> i'm very, very proud to be a part of this weekend. ♪ without you >> reporter: to usher. >> we got another four years. >> reporter: kicking off the festivities at saturday's kids' inaugural ball, hosted by dr. jill biden and the first lady. >> this is what inauguration is all about. it's about celebrating who we are, as americans. >> reporter: this year's inauguration is expected to be a bit more low-key than the president's first in 2009. >> how does he recapture the magic the second time around